The present disclosure relates generally to DNAzymes, and more particularly to sensors incorporating the DNAzymes.
Many metals pose a risk as environmental contaminants. Some methods for metal analysis, such as atomic absorption spectrometry, inductively coupled plasma mass spectrometry, and anodic stripping voltammetry, often involve sophisticated equipment and sample pre-treatment.
DNAzymes (i.e., DNA enzymes or deoxyribozymes) have been isolated through in vitro selection (Selective Evolution of Ligands through EXponential Enrichment-SELEX) protocols (Sen and Geyer, 1998; Joyce, 2004; Fiammengo and Jaschke, 2005). A variety of deoxyribozymes have been isolated in vitro that are capable of catalyzing different chemical reactions, including RNA or DNA ligation (Carmi et al., 1998; Cruz et al., 2004), phosphorylation (Li and Breaker, 1999), cleavage of phosphoramidate bonds (Burmiester et al., 1997) porphyrin metallation (Li and Sen, 1996) and DNA or RNA cleavage (Carmi et al., 1996; Ting et al., 2004). DNAzymes generally have high stability against chemical and nuclease degradations. This, in combination with the catalytic activity and substrate recognition ability, makes RNA-cleaving DNAzymes potential reagents for biochemical, environmental and pharmaceutical applications.
Biomolecular recognition tools (such as DNAzyme-based ligands (catalytic DNA)) have been developed in recent years. Such tools have the potential to be highly selective and rapid sensors for the detection of transition metal ions. The focus of such tools has been on divalent metal cations. The ligands that emerge from in vitro selections generally range from 20 to 50 nucleotides in length. Due, at least in part, to their high specificity and high catalytic rates (generally below 1.0 min−1), these sensors are capable of rapidly screening large numbers of samples. Development of target protocols for geochemically diverse conditions and means for attachment to matrices for relatively simple field deployment may be desirable for rendering such sensors useful to practitioners.